Dengue eye disease

Infectious eye disease in the 21st century-an overview

Infectious diseases affecting the eye often cause unilateral or asymmetric visual loss in children and people of working age. This group of conditions includes viral, bacterial, fungal and parasitic diseases, both common and rare presentations which, in aggregate, may account for a significant portion of the global visual burden. Diagnosis is frequently challenging even in specialist centres, and many disease presentations are highly regional. In an age of globalisation, an understanding of the various modes of transmission and the geographic distribution of infections can be instructive to clinicians. The impact of eye infections on global disability is currently not sufficiently captured in global prevalence studies on visual impairment and blindness, which focus on bilateral disease in the over-50s. Moreover, in many cases it is hard to differentiate between infectious and immune-mediated diseases. Since infectious eye diseases can be preventable and frequently affect younger people, we argue that in future prevalence studies they should be considered as a separate category, including estimates of disability-adjusted life years (DALY) as a measure of overall disease burden. Numbers of ocular infections are uniquely affected by outbreaks as well as endemic transmission, and their control frequently relies on collaborative partnerships that go well beyond the remit of ophthalmology, encompassing domains as various as vaccination, antibiotic development, individual healthcare, vector control, mass drug administration, food supplementation, environmental and food hygiene, epidemiological mapping, and many more. Moreover, the anticipated impacts of global warming, conflict, food poverty, urbanisation and environmental degradation are likely to magnify their importance. While remote telemedicine can be a useful aide in the diagnosis of these conditions in resource-poor areas, enhanced global reporting networks and artificial intelligence systems may ultimately be required for disease surveillance and monitoring.

Ocular Autoimmune Systemic Inflammatory Infectious Study (OASIS) - Report 6: Dengue Uveitis at a Tertiary Eye Institution in Singapore

OBJECTIVES

To identify the characteristics, treatment, and visual outcomes of dengue uveitis at a tertiary eye care centre in Singapore.

METHODS

Retrospective case record review of all consecutive dengue uveitis patients (2004 to 2015) from the Ocular Autoimmune Systemic Inflammatory and Infectious Study (OASIS) database.

RESULTS

Fifty-four patients were identified from the OASIS database. The most common ocular symptom was blurring of vision (n = 41, 75.9%), followed by floaters (n = 9, 17.0%), scotoma (n = 5, 9.3%), and metamorphopsia (n = 3, 5.7%). Scotoma based on history, Amsler grid, and perimetry accounted for 27 (50%) patients. Majority presented with either a posterior uveitis or retinal vasculitis (n = 51, 94.4%). Treatments ranged from close observation for spontaneous improvement, to the use of high-dose corticosteroids.

CONCLUSIONS

Dengue uveitis may present with a spectrum of disease manifestations including posterior uveitis, vasculitis, and macula edema. Scotoma is significant and may be found on history taking, Amsler charting, and perimetry.

Ocular Manifestations of Flavivirus Infections

Flaviviruses are a group of positive-sense, single-stranded RNA viruses predominantly transmitted by arthropods (mainly mosquitoes) that cause severe endemic infections and epidemics on a global scale. They represent a major cause of systemic morbidity and death and are expanding worldwide. Among this group, dengue fever, the West Nile virus, yellow fever, Japanese Encephalitis, and, recently, the Zika virus have been linked to a spectrum of ocular manifestations. These manifestations encompass subconjunctival hemorrhages and conjunctivitis, anterior and posterior uveitis (inclusive of vitritis, chorioretinitis, and retinal vasculitis), maculopathy, retinal hemorrhages, and optic neuritis. Clinical diagnosis of these infectious diseases is primarily based on epidemiological data, history, systemic symptoms and signs, and the pattern of ocular involvement. Diagnosis confirmation relies on laboratory testing, including RT-PCR and serological testing. Ocular involvement typically follows a self-limited course but can result in irreversible visual impairment. Effective treatments of flavivirus infections are currently unavailable. Prevention remains the mainstay for arthropod vector and zoonotic disease control. Effective vaccines are available only for the yellow fever virus, dengue virus, and Japanese Encephalitis virus. This review comprehensively summarizes the current knowledge regarding the ophthalmic manifestations of the foremost flavivirus-associated human diseases.

Dengue hemorrhagic fever: a growing global menace

Dengue virus is an arthropod-borne virus, transmitted by Aedes aegypti among humans. In this review, we discussed the epidemiology of dengue hemorrhagic fever (DHF) as well as the disease's natural history, cycles of transmission, clinical diagnosis, aetiology, prevention, therapy, and management. A systematic literature search was done by databases such as PubMed and Google Scholar using search terms, 'dengue fever', 'symptoms and causes of dengue fever', 'dengue virus transmission', and 'strategies to control dengue'. We reviewed relevant literature to identify hazards related to DHF and the most recent recommendations for its management and prevention. Clinical signs and symptoms of dengue infection range from mild dengue fever (DF) to potentially lethal conditions like DHF or dengue shock syndrome (DSS). Acute-onset high fever, muscle and joint pain, myalgia, a rash on the skin, hemorrhagic episodes, and circulatory shock are among the most common symptoms. An early diagnosis is vital to lower mortality. As dengue virus infections are self-limiting, but in tropical and subtropical areas, dengue infection has become a public health concern. Hence, developing and executing long-term control policies that can reduce the global burden of DHF is a major issue for public health specialists everywhere.

Dengue Uveitis - A Major Review

Dengue fever is a significant global public health concern with increasing incidence over the past two decades. The symptoms range from mild to severe, including fever, headache, rash, and joint pain. Ocular complications are prevalent among hospitalized patients, estimated to be between 10% and 40.3%, with varying incidences based on the serotype and severity of dengue. These complications can be hemorrhagic or inflammatory and typically occur after the onset of fever. Modern diagnostic tools such as Optical Coherence Tomography (OCT) and Fundus Fluorescein Angiography (FFA) have enabled physicians to better understand the extent of ocular involvement and guide treatment. This article provides an updated overview of the various manifestations of dengue uveitis, including their diagnosis and treatment.

Ophthalmic complications during the dengue epidemic in Reunion Island in 2020: a case series and review of the literature

INTRODUCTION

Dengue is an arboviral disease transmitted by the dengue virus, whose vectors are Aedes aegypti and Aedes albopictus. The acute phase with its cohort of well-known symptoms is usually spontaneously favorable. Since 2020 in Reunion Island, a new symptom has appeared: the ocular damage of dengue fever, which has already been described in South Asia and South-East Asia. We therefore decided to describe the clinical, biological, ophthalmological, therapeutic, and outcomes of patients with ocular manifestations during dengue fever in Reunion Island in 2020.

PATIENTS AND METHODS

This was a retrospective observational study. Patients were included from January 2020 to August 2020 and then reassessed by teleconsultation 1 year later. The patients were identified from the French public health surveillance network by all ophthalmologists on the island. Medical data were collected directly from medical records.

RESULTS

Twenty-eight patients were included. The mean age was 41.9 years. Ocular involvement occurred approximately 9.2 days after the onset of dengue symptoms. The main symptoms were scotoma (71.4%) and sudden decrease of visual acuity (39.2%). Eighteen patients (64.2%) had macular involvement. Fourteen patients were treated with oral or intravenous corticosteroids. Twenty-two (78.5%) patients were evaluated by telephone one year later. Scotoma and decreased visual acuity persisted in 15 patients. Thirteen patients (59%) were bothered by night driving, 32% of patients had reading difficulties and 27% of patients became sensitive to prolonged exposure to screens.

CONCLUSION

Ocular complications of dengue require early and collegial management to limit the risk of long-term sequelae. Further studies on the characteristics and complications of dengue fever are needed to better understand this disease.

From dengue outbreaks to endemicity: Reunion Island, France, 2018 to 2021

BackgroundAfter 40 years of limited viral circulation, Reunion Island has since 2018 experienced recurrent dengue outbreaks of increasing intensity and severity.AimWe aimed to report on the epidemiology and characteristics of dengue in Reunion Island between 2018 and 2021.MethodsBetween 2018 and August 2021, we systematically collected data on dengue cases via an automated transmission system between the health authorities and the medical laboratories. We set up additional surveillance systems for dengue-related activity in primary care, in emergency departments and in inpatient departments.ResultsUntil 2020, despite numerous cases, outbreaks had a limited public health impact because of few severe cases, low lethality and no heavy burden for the health care system. In 2021, however, the number of severe cases increased (from 0.4% of all cases in 2018 to 0.8% in 2021), as did the number of paediatric cases (from 8% in 2018 to 15% in 2021) and atypical clinical forms of dengue (108 cases of post-dengue maculopathy). Of note, haemorrhagic forms were rare and multi-organ failure was the most frequent severity throughout the study period. In parallel, the dominant serotype switched from DENV2 to DENV1 in 2020 and DENV1 became the only serotype detected in 2021.ConclusionThese findings indicate that dengue is becoming endemic in Reunion Island. Since comorbidities associated with severity of dengue are common in the population, health authorities should carefully consider the impact of dengue when addressing public health policies.

Clinical Characteristics and Outcomes Among Travelers With Severe Dengue : A GeoSentinel Analysis

BACKGROUND

Dengue virus is a flavivirus transmitted by Aedes mosquitoes and is an important cause of illness worldwide. Data on the severity of travel-associated dengue illness are limited.

OBJECTIVE

To describe the epidemiology, clinical characteristics, and outcomes among international travelers with severe dengue or dengue with warning signs as defined by the 2009 World Health Organization classification (that is, complicated dengue).

DESIGN

Retrospective chart review and analysis of travelers with complicated dengue reported to GeoSentinel from January 2007 through July 2022.

SETTING

20 of 71 international GeoSentinel sites.

PATIENTS

Returning travelers with complicated dengue.

MEASUREMENTS

Routinely collected surveillance data plus chart review with abstraction of clinical information using predefined grading criteria to characterize the manifestations of complicated dengue.

RESULTS

Of 5958 patients with dengue, 95 (2%) had complicated dengue. Eighty-six (91%) patients had a supplemental questionnaire completed. Eighty-five of 86 (99%) patients had warning signs, and 27 (31%) were classified as severe. Median age was 34 years (range, 8 to 91 years); 48 (56%) were female. Patients acquired dengue most frequently in the Caribbean (n = 27 [31%]) and Southeast Asia (n = 21 [24%]). Frequent reasons for travel were tourism (46%) and visiting friends and relatives (32%). Twenty-one of 84 (25%) patients had comorbidities. Seventy-eight (91%) patients were hospitalized. One patient died of nondengue-related illnesses. Common laboratory findings and signs were thrombocytopenia (78%), elevated aminotransferase (62%), bleeding (52%), and plasma leakage (20%). Among severe cases, ophthalmologic pathology (n = 3), severe liver disease (n = 3), myocarditis (n = 2), and neurologic symptoms (n = 2) were reported. Of 44 patients with serologic data, 32 confirmed cases were classified as primary dengue (IgM+/IgG-) and 12 as secondary (IgM-/IgG+) dengue.

LIMITATIONS

Data for some variables could not be retrieved by chart review for some patients. The generalizability of our observations may be limited.

CONCLUSION

Complicated dengue is relatively rare in travelers. Clinicians should monitor patients with dengue closely for warning signs that may indicate progression to severe disease. Risk factors for developing complications of dengue in travelers need further prospective study.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention, International Society of Travel Medicine, Public Health Agency of Canada, and GeoSentinel Foundation.

Dengue Virus Infection of Human Retinal Müller Glial Cells

Retinopathy is a recently recognized complication of dengue, affecting up to 10% of hospitalized patients. Research on the pathogenesis has focused largely on effects of dengue virus (DENV) at the blood-retinal barrier. Involvement of retinal Müller glial cells has received little attention, although this cell population contributes to the pathology of other intraocular infections. The goal of our work was to establish the susceptibility of Müller cells to infection with DENV and to identify characteristics of the cellular antiviral, inflammatory, and immunomodulatory responses to DENV infection in vitro. Primary human Müller cell isolates and the MIO-M1 human Müller cell line were infected with the laboratory-adapted Mon601 strain and DENV serotype 1 and 2 field isolates, and cell-DENV interactions were investigated by immunolabelling and quantitative real-time polymerase chain reaction. Müller cells were susceptible to DENV infection, but experiments involving primary cell isolates indicated inter-individual variation. Viral infection induced an inflammatory response (including tumour necrosis factor-α, interleukin [IL]-1β, and IL-6) and an immunomodulatory response (including programmed death-ligand [PD-L]1 and PD-L2). The type I interferon response was muted in the Müller cell line compared to primary cell isolates. The highest infectivity and cell responses were observed in the laboratory-adapted strain, and overall, infectivity and cell responses were stronger in DENV2 strains. This work demonstrates that Müller cells mount an antiviral and immune response to DENV infection, and that this response varies across cell isolates and DENV strain. The research provides a direction for future efforts to understand the role of human retinal Müller glial cells in dengue retinopathy.

A Case Report of Dengue-Associated Maculopathy With Literature Review

We report a case of dengue-associated maculopathy in a healthy adult. A 31-year-old lady with dengue fever presented with both eye sudden, painless blurry vision in the left eye. On examination, the best-corrected visual acuity was 6/18 in her right eye and 2/60 in her left eye. Anterior segment examination was unremarkable. Fundi showed bilateral macula edema with cotton wool spots. Optical coherence tomography (OCT) macula scan was suggestive of bilateral macula edema, with higher severity in the left eye. She was started on intravenous methylprednisolone 500mg once daily for three days. Upon completion of steroids, her right eye visual acuity improved to 6/6 however her left eye vision worsened to 3/60 after six months. Her OCT six months later showed resolved macula edema on both eyes. Ocular manifestation associated with dengue fever is rare but may result in permanent visual impairment. The use of high-dose steroids helps in improving visual acuity.

Dengue fever ophthalmic manifestations: A review and update

Dengue fever, the most common arbovirus disease, affects an estimated 390 million people annually. Dengue virus (DENV) is an RNA virus of the Flaviviridae family with four different serotypes. Dengue haemorrhagic fever is the deadliest form of dengue infection and is characterised by thrombocytopaenia, hypotension, and the possibility of multi-system organ failure. The mechanism hypothesised for DENV viral replication is intrinsic antibody-dependent enhancement, which refers to Fcγ receptor-mediated viral amplification. This hypothesis suggests that the internalisation of DENV through the Fcγ receptor inhibits antiviral genes by suppressing type-1 interferon-mediated antiviral responses. DENV NS1 antibodies can promote the release of various inflammatory mediators in the nuclear transcription factor pathway (NF-κB-dependent), including monocyte chemoattractant protein (MCP)-1, interleukin (IL)-6, and IL-8. As a result, MCP-1 increases ICAM-1 expression and facilitates leukocyte transmigration. In addition, anti-DENV NS1 antibodies induce endothelial cell apoptosis via a nitric oxide-regulated pathway. A chain reaction involving pre-existing DENV heterotypic antibodies and innate immune cells causes dysfunction in complement system activity and contributes to the action of autoantibodies and anti-endothelial cells, resulting in endothelial cell dysfunction, blood-retinal barrier breakdown, haemorrhage, and plasma leakage. A spectrum of ocular diseases associated with DENV infection, ranging from haemorrhagic to inflammatory manifestations, has been reported in the literature. Although rare, ophthalmic manifestations can occur in both the anterior and posterior segments and are usually associated with thrombocytopenia. The most common ocular complication is haemorrhage. However, ophthalmic complications, such as anterior uveitis and vasculitis, suggest an immune-mediated pathogenesis.

Myopic Shift in a Patient with Dengue Fever

PURPOSE

This report aims to present a case of dengue-related myopic shift.

METHODS

This is a case report of a patient with dengue-related transient myopia, and demonstrates possible underlying pathophysiology.

RESULTS

A 38-year-old gentleman presented with bilateral blurring of vision with an unaided visual acuity (VA) of 6/120 bilaterally. He had a refractive error of -2.50 dioptres in the right eye, and -3.50 dioptres in the left eye. Ultrasound biomicroscopy (UBM) revealed suprachoroidal effusion with anterior displacement of the lens-iris complex bilaterally. Biometry performed showed lens thickness (LT) of 4.47 mm in the right eye, and 4.65 mm in the left eye. His unaided VA was noted to be 6/6 bilaterally 4 days later.

CONCLUSIONS

Dengue-related myopic shift was likely secondary to two mechanisms. Firstly, suprachoroidal effusion resulted in an anterior displacement of the lens-iris complex. Secondly, there was an increase in the antero-posterior diameter of the lens, resulting in index myopia.

Pars Plana Vitrectomy for a Sub-Internal Limiting Membrane Hemorrhage and Vitreous Hemorrhage Secondary to Dengue Fever: A Case Report

Although rare, dengue fever-associated ocular manifestations are a valid cause of visual impairment. Clinicians usually have a dilemma between vitrectomy and medical management if there is an associated vitreous hemorrhage. Vitrectomy has been rarely reported previously in the management of vitreous hemorrhage secondary to dengue fever.

We report a case of a young adult who presented with bilateral vitreous hemorrhages. The diagnosis of dengue was confirmed by serology and a typical epidemiological context. The patient presented already having undergone yttrium aluminum garnet (YAG) laser hyaloidotomy for preretinal hemorrhage in the other eye, with a subsequent vitreous spread of the hemorrhage. Vitrectomy with internal limiting membrane (ILM) peeling was performed for the affected eye and the visual acuity was fully regained after a few weeks.

Dengue fever can present with dense or sub-ILM hemorrhages. In our case, the vision quickly recovered after vitrectomy and ILM peeling. We, therefore, recommend early vitrectomy in cases with vitreous hemorrhage associated with sub-ILM involvement so as not to delay visual recovery.

Optical Coherence Tomography Findings in Infectious Posterior Uveitis

PURPOSE

To describe and illustrate the main optical coherence tomography (OCT) findings of infectious uveitis.

METHODS

Narrative review.

RESULTS

Posterior segment OCT in patients with infectious uveitis reveals posterior hyaloid face precipitates, superficial retinal precipitates and infiltrates, foveolitis, retinitis, neuro-retinitis, choroidal granulomas, and choroiditis as main imaging biomarkers. Some of these features are specific to the underlying causing etiology and may support the diagnosis and the initiation of treatment. Some OCT features disappear completely with resolution; some others are associated with irreversible retinal damage.

CONCLUSIONS

OCT identifies different features of infectious uveitis into the vitreous, the retina, and the choroid. OCT characteristics, combined with other multimodal imaging features, are helpful in the differential diagnosis of infectious uveitis, the early detection of complications, and the assessment of the response to therapy.

Infection of Human Retinal Pigment Epithelial Cells with Dengue Virus Strains Isolated during Outbreaks in Singapore

Prevalence of dengue retinopathy varies across epidemics, with the disease linked to circulation of dengue virus serotype 1 (DENV-1). The retinal pigment epithelium has been implicated in the pathology. We investigated infectivity, molecular response, and barrier function of epithelial cells inoculated with DENV strains from different outbreaks in Singapore. Monolayers of human retinal pigment epithelial cells (multiple primary cell isolates and the ARPE-19 cell line) were inoculated with six DENV strains, at multiplicity of infection of 10; uninfected and recombinant strain-infected controls were included where relevant. Infectivity and cell response were assessed primarily by RT-qPCR on total cellular RNA, and barrier function was evaluated as electrical resistance across monolayers. Higher viral RNA loads were measured in human retinal pigment epithelial cells infected with DENV-1 strains from the 2005 Singapore epidemic, when retinopathy was prevalent, versus DENV-1 strains from the 2007 Singapore epidemic, when retinopathy was not observed. Type I interferon (IFN) transcripts (IFN-β and multiple IFN-stimulated genes) were up-regulated, and impact on barrier function was more pronounced, for cells infected with DENV-1 strains from the 2005 versus the 2007 Singapore epidemics. Aside from serotype, strain of DENV may determine the potential to induce retinal pathology. Identification of molecular markers of disease-associated DENV strains may provide insights into the pathogenesis of dengue retinopathy.

World Health Organization High Priority Pathogens: Ophthalmic Disease Findings and Vision Health Perspectives

Recent Ebola epidemics, the ongoing COVID-19 pandemic, and emerging infectious disease threats have highlighted the importance of global infectious diseases and responses to public health emergencies. Ophthalmologists are essential health care workers who provide urgent and emergent vision care services during outbreaks and address the ocular consequences of epidemic and pandemic infectious diseases. In 2017, the World Health Organization (WHO) identified high priority pathogens likely to cause a future epidemic with the goal of guiding research and development to improve diagnostic tests, vaccines, and medicines. These measures were necessary to better inform and respond to public health emergencies. Given the ocular complications associated with emerging infectious diseases, there is a need to recognize the ophthalmic sequelae for future vision health preparedness for potential future outbreaks. The WHO High Priority pathogens list provides a roadmap for ophthalmologists and subspecialty providers that will guide strategic areas of research for clinical care and preparedness for future pandemic threats. This review summarizes these key viral pathogens, summarizes major systemic disease findings, and delineates relevant ocular complications of the WHO High Priority pathogens list, including Crimean-Congo hemorrhagic fever, Filovirus diseases (Ebola virus disease and Marburg hemorrhagic fever), human Coronaviruses, Lassa Fever, Nipah virus infection, Zika, and Rift Valley fever.

Management of a case of bilateral dengue maculopathy with intravitreal steroid therapy

Bilateral sight threatening macular and optic nerve inflammation may occur with dengue fever, necessitating the use of systemic steroids. We report a case of bilateral dengue maculopathy in an elderly woman managed with targeted intravitreal steroid therapy. A 63-year-old woman presented with acute-onset painless diminution of vision in both eyes following a dengue fever episode. She had bilateral foveal inflammatory lesions, macular oedema, small vessel occlusions at the macula and scattered retinal haemorrhages and cotton-wool spots. Following systemic evaluation, intravitreal triamcinolone acetonide injection was performed in both eyes at an interval of 3 days. The foveal lesion and macular oedema resolved quickly in both eyes with a normal foveal architecture at the end of 6-week follow-up. The visual acuity improved considerably in both eyes. Inflammatory retinopathy in dengue fever may be managed with a targeted intravitreal steroid injection approach.

Case Report: Acute Vision Loss in a Young Returning Traveler with Dengue Fever

Ocular complications are rare in patients with dengue fever, but may cause permanent loss of vision. We present the case of a 29-year-old German woman who developed severe acute vision loss because of dengue-associated maculopathy after traveling to Vietnam and Cambodia. Initially, the optical coherence tomography showed detachment of the retinal pigment epithelium, a central shift in the retinal pigmentation and intraretinal cysts. The patient was hospitalized and treated with a short course of intravenous prednisolone. Vision improved, and the patient showed full recovery at 9 months after the onset. This case highlights the importance of awareness and adequate management for ocular involvement in patients with dengue fever, including travelers.

Retinal Vasculitis with Macular Infarction: A Dengue-related Ophthalmic Complication

Introduction

Dengue-associated ocular complications are increasing owing to the rising global burden of dengue fever. We intend to highlight a rare and sight-threatening complication of this disease.

Case Details

A 44-year-old male, with prior history of dengue fever, presented with diminution of vision in both eyes for 10 days. At presentation, his best-corrected visual acuity was 1/60 in the right eye and 6/18 in the left eye. Anterior segment findings were unremarkable. Fundus examination revealed vitritis, perivascular exudates, intraretinal hemorrhages, macular edema, peripapillary retinal whitening and cotton wool spots in both eyes suggestive of vasculitis, with additional retinal whitening affecting the right macula. Fundus fluorescein angiography revealed disc and perivascular leakage limited to posterior pole along with patches of blocked fluorescence. In addition, there was capillary nonperfusion due to occlusion of multiple small arterioles supplying the macula of right eye confirming macular ischemia. Macular edema with subretinal fluid in both eyes was evident on optical coherence tomography. Treatment was attempted with intravenous methylprednisolone which was futile even after three days of administration.

Conclusion

We report a case of retinal vasculitis with macular infarction attributed to dengue fever. Although uncommon, dengue-associated ocular complications can lead to irreversible visual loss. Therefore, clinicians should keep this disease entity in mind while evaluating febrile patients with visual complaints in dengue endemic regions.

Post-fever retinitis - Newer concepts

Post-fever retinitis (PFR) is an infectious or para-infectious uveitic entity caused by bacterial or viral agents and seen mainly in tropical countries. Systemic symptoms such as joint pain, skin rash are common during the febrile stage. On the basis of only clinical presentation, it is difficult to pin-point the exact etiology for PFR. Serological investigations, polymerase chain reaction, and knowledge of concurrent epidemics in the community may help to identify the etiological organism. Bacterial causes of PFR such as rickettsia and typhoid are treated with systemic antibiotics, with or without systemic steroid therapy, whereas PFR of viral causes such as chikungunya, dengue, West Nile virus, and Zika virus have no specific treatment and are managed with steroids. Nevertheless, many authors have advocated mere observation and the uveitis resolved with its natural course of the disease. In this article, we have discussed the clinical features, pathogenesis, investigations, and management of PFR.

Dengue virus infects the mouse eye following systemic or intracranial infection and induces inflammatory responses

Dengue virus (DENV) infection is associated with clinical ocular presentations and here DENV infection of the eye was assessed in mice. In an AG129 mouse model of antibody-dependent enhancement of DENV infection, DENV RNA was detected in the eye and vascular changes were present in the retinae. Intraocular CD8 and IFN-γ mRNA were increased in mice born to DENV-naïve, but not DENV-immune mothers, while TNF-α mRNA was induced and significantly higher in mice born to DENV-immune than DENV-naïve mothers. DENV RNA was detected in the eye following intracranial DENV infection and CD8 mRNA but not IFN-γ nor TNF-α were induced. In all models, viperin was increased following DENV infection. Thus, DENV in the circulation or the brain can infect the eye and stimulate innate immune responses, with induction of viperin as one response that consistently occurs in multiple DENV eye-infection models in both an IFN-dependent and independent manner.

Case Report: A Case of Acute Intravascular Hemolysis in Dengue Fever

Acute intravascular hemolysis (AIH) with hemoglobinuria is a rare complication of dengue viral infection. Review of the literature revealed only one report of AIH as a complication of dengue fever (DF). We report a case of AIH with massive hemoglobinuria in a 17-year-old Sri Lankan male, in the febrile phase of DF. This unusual and rare complication warranted forced diuresis, to prevent acute kidney injury. This was a departure from the recommended fluid therapy for DF.

Ocular manifestations of dengue

PURPOSE OF REVIEW

There are an increasing number of publications related to dengue ophthalmic manifestations and multimodality imaging related to dengue. This review summarizes the current literature, describe ocular manifestations, current using of ocular imaging/investigations, and management of ocular dengue.

RECENT FINDINGS

Ocular manifestations of dengue can be present in many stages of dengue fever including after the resolution of systemic disease. Most cases of ocular dengue will exhibit an improvement in vision spontaneously over time. Multimodal imaging such as optical coherence tomography, optical coherence tomography angiography, near-infrared imaging, and microperimetry plays an important role in the diagnosis, follow-up, quantitative measure, and help to understand the disease progression.

SUMMARY

Dengue fever can lead to a variety of ocular manifestations. The mechanisms underlying dengue-related ocular complications remain unclear. Immune-mediated mechanisms and direct viral invasion are thought to play an important role. Ophthalmologists should carefully assess patients with dengue-related ophthalmic disease because some patients may have poor visual acuity and exhibit refractoriness to treatment. Treatment with systemic corticosteroids may benefit those patients with poor presenting visual acuity, progressive ocular symptoms, and lesions involving the optic nerve and/or threatening the macula.

Unusual clinical manifestations of dengue disease - Real or imagined?

The disease caused by each of the four serotypes of dengue virus (DENV) have plagued humans since last century. Symptoms of dengue virus (DENV) infection range from asymptomatic to dengue fever (DF) to severe dengue disease (SDD). One third of the world's population lives in regions with active urban DENV transmission, and thousands of serologically naïve travelers visit these areas annually, making a significant portion of the human population at risk of being infected. Even though lifelong immunity to the homotypic serotype is achieved after a primary DENV infection. Heterotypic DENV infections may be exacerbated by a pre-existing immune memory to the primary infection and can result in an increased probability of severe disease. Not only, age, comorbidities and presence of antibodies transferred passively from dengue-immune mother to infants are considered risk factors to dengue severe forms. Plasma leakage and multiple organ impairment are well documented in the literature, affecting liver, lung, brain, muscle, and kidney. However, unusual manifestation, severe or not, have been reported and may require medical attention. This review will summarize and discuss the increasing reports of unusual manifestations in the clinical course of dengue infection.

Characterization of Retinopathy Among Patients With Yellow Fever During 2 Outbreaks in Southeastern Brazil

Importance

Yellow fever still threatens people in endemic areas, and besides conjunctival icterus, little is known about the ocular changes that occur in these patients.

Objective

To characterize retinal changes in patients with confirmed yellow fever during 2 recent outbreaks of the disease in Minas Gerais, Southeastern Brazil.

Design, Setting, and Participants

This cross-sectional, observational study conducted at a single referral center for infectious diseases in Southeastern Brazil collected data between January 2017 and February 2018 from 94 consecutive patients with suspicion of yellow fever who were eligible for the study.

Main Outcomes and Measures

Patients underwent ophthalmic examination. Clinical findings, laboratory results, and occurrence of retinopathy and death during hospitalization were reported, including age, sex, comorbidities, disease severity, serum aspartate aminotransferase level, total bilirubin level, serum creatinine level, arterial lactate level, international normalized ratio, and platelet count at hospital admission.

Results

In total, 64 patients were included who had received a confirmed diagnosis of yellow fever, with a median (interquartile range) age of 47 (38-56) years, and 12 patients (19%) were women. Twenty eyes (16%) of 13 patients (20%) had retinopathy at the same time as yellow fever. The most common fundus changes among the 20 eyes were retinal nerve fiber layer infarcts (11 [55%]), superficial hemorrhages (7 [35%]) and grayish deep lesions (6 [30%]), possibly at the level of the outer retina or choroid. Aspartate aminotransferase levels higher than 3000 U/L (odds ratio [OR], 14.2; 95% CI, 3.5-77.8; P < .001), total bilirubin levels higher than 2.3 mg/dL (OR, 20.0; 95% CI, 4.4-159.7; P < .001), serum creatinine levels higher than 2.0 mg/dL (OR, 8.2; 95% CI, 2.1-36.0; P = .003), arterial lactate levels higher than 17.1/mg/dL (OR, 4.6; 95% CI, 1.1-19.0; P = .03), platelet count lower than 94 × 103/μL (OR, 7.8; 95% CI, 1.8-59.9; P = .004), and classification of disease as severe (OR, 11.7; 95% CI, 2.0-301.0; P = .003) were associated with retinopathy. Arterial hypertension, diabetes, international normalized ratio, and death were not associated with retinopathy.

Conclusions and Relevance

Retinopathy was present in 20% of patients with yellow fever and appeared to be associated with more severe systemic disease. Retinal nerve fiber layer infarcts and superficial hemorrhages, but not the grayish deep lesions, resembled those associated with other flavivirus (eg, dengue virus) infections. The clinical relevance of these findings may warrant further investigation.

The eye in dengue fever, a rarely appreciated aspect of dengue expanded syndrome: a case report

BACKGROUND

Dengue fever is a mosquito-borne illness prevalent mainly in the tropics. It is feared for causing the dengue hemorrhagic spectrum of the disease leading to significant morbidity and mortality. Its rarer manifestations are categorized as the expanded dengue syndrome, and though being recognized, they are not fully appreciated and understood. The involvement of the eye in dengue fever is one such phenomenon.

CASE PRESENTATION

A 27-year-old South-Asian woman presented on day 2 of dengue fever, without capillary leakage, for further management. Despite developing hepatitis, she had an otherwise uncomplicated progression of the illness because she did not develop capillary leakage. On day 8 of the illness, she had the lowest platelet count and developed bilateral blurred vision. Examination revealed that only gross movements were detected in the left eye, and the right eye had a visual acuity of 6/9. She was diagnosed with foveolitis in the right eye and central serous chorioretinopathy in the left eye, along with hemorrhages in both eyes. These were confirmed by funduscopy, fluorescein angiography, optical coherence tomography, and macular scans. She received systemic and intravitreal steroids and was assessed regularly. After 6 months of observation, her visual acuity was 6/6 in the right eye and 6/9 in the left eye, which remained the same thereafter.

DISCUSSION

The exact mechanism of eye involvement in dengue viral infection is poorly understood. Multiple causes have been suspected and include viral factors, immune mediation, capillary leakage, stress, and hemorrhage. Eye involvement is classically seen at the lowest platelet count and when the count begins to rise. Though symptoms are nonpathognomonic, blurring of vision is the commonest complaint, but the range of presentation is extensive and variable. Ophthalmological assessment and funduscopy are very useful in addition to advanced assessments. There is no clear consensus on management; suggestions range from conservative care to aggressive steroid therapy with immune modulation and even ophthalmological intervention. Recovery can be full or partial with a variable time scale.

CONCLUSION

The extensive spectrum of possible visual symptoms should prompt the clinician to suspect any visual complaint as potential dengue eye involvement. Guided studies and screening are needed to better understand the true incidence of eye involvement in dengue fever.

Pneumatic Displacement of a Dense Sub-inner Limiting Membrane Pre-macular Hemorrhage in Dengue Maculopathy: A Novel Treatment Approach

Sub-inner limiting membrane (ILM) hemorrhage is a rare presenting feature of dengue maculopathy. A 24-year-old man in active military service who was recently treated for dengue hemorrhagic fever presented with sub-ILM bleeding in right eye (dominant eye) with profound diminution of vision. Spectral domain optical coherence tomography and fundus fluorescein angiography confirmed sub-ILM hemorrhage with no evidence of vasculitis/venous occlusion or neovascularization. He refused active surgical management by pars plana vitrectomy and was treated with pneumatic tamponade of C3F8 (100%) gas with prone positioning in order to achieve faster visual recovery. He responded well to treatment with complete visual recovery in 1 week. This case report documents for the first time treatment of sub-ILM hemorrhage in the premacular area with pneumatic tamponade in prone position leading to rapid and complete visual recovery in a patient with dengue maculopathy. This novel approach can be employed for patients who are ineligible for more active surgical management.

Panophthalmitis in a patient with dengue fever

Dengue fever is known for its life-threatening complications of bleeding and capillary leak syndrome. We report an unusual complication of dengue fever causing panophthalmitis, leading to rapidly progressive painful visual loss within days. Later on, the patient developed secondary bacterial infection of the eyeball and developed multiple brain abscesses due to spread of infection from the eyeball. Culture from pus swab of the right eye grew Staphylococcus epidermidis. The patient was promptly treated with broad spectrum antibiotics and after stabilisation, evisceration of the affected eye was done. Supportive therapy in the form of mechanical ventilation in view of poor sensorium, platelet transfusions for thrombocytopenia and guided fluid therapy was also provided. After multiple challenges in the management of the patient, fortunately, the patient survived but we failed to save his right eye. Therefore, it is necessary to carefully examine all vital organs at an early stage to prevent unfortunate outcome.

Ocular Manifestations of Mosquito-Transmitted Diseases

Of the 3,548 known mosquito species, about 100 transmit human diseases. Mosquitoes are distributed globally throughout tropical and temperate regions where standing water sources are available for egg laying and the maturation of larva. Female mosquitoes require blood meals for egg production. This is the main pathway for disease transmission. Mosquitoes carry several pathogenic organisms responsible for significant ocular pathology and vision loss including West Nile, Rift Valley, chikungunya, dengue viruses, various encephalitis viruses, malarial parasites, Francisella tularensis, microfilarial parasites, including Dirofilaria, Wuchereria, and Brugia spp., and human botfly larvae. Health care providers may not be familiar with many of these mosquito-transmitted diseases or their associated ocular findings delaying diagnosis, treatment, and recovery of visual function. This article aims to provide an overview of the ocular manifestations associated with mosquito-transmitted diseases.

Emerging Viral Infections Causing Anterior Uveitis

PURPOSE

To review the systemic and ocular manifestations of specific emergent viral infectious diseases relevant to the ophthalmologist with particular emphasis on anterior uveitis Methods: Review of literature.

RESULTS

Arboviral diseases are among the most important emergent and resurgent human infections, occurring mostly in tropical and subtropical zones, but appearing in virtually all regions of the world as a result of climate change, travel, and globalization. Arboviral infections are transmitted to humans by the bite of hematophagous arthropods, mainly mosquitoes. Systemic disease may range from asymptomatic to life-threatening. A wide variety of ocular manifestations, including uveitis, has been reported in association with these emerging viral diseases. Numerous viruses other than arboviruses also have been recently recognized as a potential cause of uveitis.

CONCLUSIONS

Proper clinical diagnosis of any emerging infectious disease is based on epidemiological data, history, systemic symptoms and signs, and the pattern of ocular involvement. The diagnosis is usually confirmed by detection of virus-specific DNA or antivirus antibodies in serum.

Emerging infectious uveitis: Chikungunya, dengue, Zika and Ebola: A review

Recently recognized forms of uveitis include intraocular inflammations that occur during or following one of several emerging infectious diseases: chikungunya fever, dengue, Zika virus disease and Ebola virus disease. Anterior, intermediate, posterior and pan-uveitis have been described in individuals infected with chikungunya virus. Persons who contract dengue or Zika viruses also may develop different types of uveitis in the course of the infection: maculopathy is a common manifestation of dengue eye disease, and Zika eye disease may cause hypertensive anterior uveitis or mimic a white dot syndrome. Up to one-third of Ebola survivors develop aggressive uveitis, which is frequently associated with vision loss and complicated by cataract. There are no specific anti-viral drugs for these forms of uveitis, and thus treatment is largely supportive. In this article, we summarize the systemic infectious diseases and virology, and describe the clinical presentations, outcomes and management of emerging viral forms of uveitis.

Infectious uveitis: an Asian perspective

Several intraocular infections can present with protean manifestations posing major diagnostic and management challenges. Infections such as tuberculosis, dengue and chikungunya fever have continued to remain major endemic diseases that are associated with uveitis in the Asia Pacific region. These entities often require a high index of clinical suspicion and laboratory analysis including assays of ocular fluids and/or tissues for confirmation of the diagnosis. Infectious uveitis caused by tuberculosis, dengue and chikungunya can present with characteristic clinical features and imaging findings on ancillary investigations; that may provide clue to the early diagnosis. Use of modern imaging modalities such as enhanced-depth imaging optical coherence tomography, optical coherence tomography angiography and ultra-wide field fundus photography greatly aid in the evaluation of these conditions. In the current review, we have discussed the epidemiology, clinical phenotypes, imaging characteristics, diagnosis and management of uveitis caused by tuberculosis, dengue and chikungunya.

Dengue-Induced Inflammatory, Ischemic Foveolitis and Outer Maculopathy: A Swept-Source Imaging Evaluation

PURPOSE

Dengue maculopathy can present with a unique constellation of features resulting in significant central visual morbidity. We aim to describe various findings of dengue-induced inflammatory, ischemic foveolitis, and outer maculopathy (DIII-FOM) and assess the serial changes in vitreous inflammation, retinal structure, and vascularity using swept-source OCT (SS-OCT) and OCT angiography (OCTA).

DESIGN

Retrospective case series.

PARTICIPANTS

A total of 32 eyes (16 patients; 7 male) with dengue fever (positive serology for NS1 antigen) were enrolled in the study.

METHODS

In this study, serial assessments of ocular findings and imaging using fundus photography, SS-OCT, and SS-OCTA were performed. All the patients received 0.5 to 1 mg/kg/day oral prednisolone that was tapered over 4 to 6 weeks.

MAIN OUTCOME MEASURES

Outcome measures included functional change, that is, improvement in best-corrected visual acuity (BCVA), structural changes in the vitreous and retinal layers on SS-OCT, and retinal perfusion on OCTA.

RESULTS

The mean age of the patients was 29.17±10.91 years. Swept-source OCT showed vitreous cells (32 eyes; 100%), disruption of outer retinal layers (foveolitis) (24 eyes; 75%), and conical foveal elevation (22 eyes; 68.75%). After initiation of systemic corticosteroids, all the eyes showed resolution of vitreous cells and improvement in the integrity of retinal layers. Mean BCVA improved from an initial 0.80±0.33 logarithm of the minimum angle of resolution (logMAR) to 0.23±0.36 logMAR. Retinal plexus flow deficit (superficial plexus: 0.10±0.12 mm²; deep plexus: 0.29±0.13 mm²) persisted in all eyes and correlated well with initial BCVA (P < 0.05).

CONCLUSIONS

The pathophysiology of dengue maculopathy involves both ischemic and inflammatory components. Early institution of corticosteroid therapy may help in resolution of the inflammation-driven vitreoretinal alterations, but ischemia of the deep retinal plexuses may persist and may be the cause of permanent structural and functional changes.

[Ocular manifestations of emerging arboviruses: Dengue fever, Chikungunya, Zika virus, West Nile virus, and yellow fever (French translation of the article)]

Arboviruses are viral diseases transmitted by mosquitoes and tics bites. They are a major cause of morbidity and sometimes mortality. Their expansion is constant and due in part to climate change and globalization. Mostly found in tropical regions, arboviruses are sometimes the source of epidemics in Europe. Recently, the Chikungunya virus and the Zika virus were responsible for very large epidemics impacting populations that had never been in contact with those viruses. There are currently no effective antiviral treatments or vaccines. Ocular manifestations due to those infections are thus more frequent and increasingly better described. They are sometimes, as with Zika, complicated by a congenital ocular syndrome. The goal of this review is to describe the ophthalmological manifestations of Dengue fever, Chikungunya virus, Zika virus, West Nile virus, and yellow fever.

Dengue fever-associated necrotizing scleritis: A case report with long-term follow-up

RATIONALE

Dengue fever is a notable emerging infectious disease that is now seen worldwide, with an estimated incidence of approximately 390 million cases per year. Although ocular complications are uncommon among dengue fever-infected patients, caution is needed to prevent vision loss. Here we report a potentially serious sight-threatening complication of dengue fever, dengue fever-associated necrotizing scleritis.

PATIENT CONCERNS AND DIAGNOSIS

After being bitten by mosquitoes, a 60-year-old Japanese female exhibited positive serologic tests of immunoglobulin M and G enzyme immunoassays for dengue viral infection along with a decrease of leukocytes and platelets. These findings led to a dengue fever diagnosis. Slit lamp examination of her left eye revealed a conjunctival and scleral injection, elevation of the entire circumference of the sclera, and bulging of the sclera on the nasal upper side with a patch of avascular episcleral tissue. Since additional systemic examinations identified no autoimmune diseases such as rheumatism, we diagnosed the patient as dengue fever-associated scleritis.

INTERVENTIONS

Intensive systemic and topical steroids were administrated during the initial acute phase. Over the next 15 months, the amount of steroid was tapered off.

OUTCOME

Initial findings for the scleritis gradually declined in response to steroid treatment. Although there was no recurrence of active scleritis, gradual thinning of the sclera continued to occur during the 18-year follow-up.

LESSONS

To the best of our knowledge, this is the first reported case of dengue fever-associated necrotizing scleritis with long-term follow-up. This case suggests the existence of a long-term immune-mediated mechanism during the development of the dengue fever-associated necrotizing scleritis. Dengue fever virus patients found to have red eyes need to be carefully followed and treated, as these eyes might develop thinning of the sclera that could lead to rupture of the globe, thereby resulting in blindness.

Culture-positive unilateral panophthalmitis in a serology-positive case of dengue hemorrhagic fever

Dengue fever, a mosquito-borne disease commonly found in the tropics, is one of the most prevalent forms of Flavivirus infection in humans. Symptomatically, it is characterized by fever, arthralgia, headache, and rash. Ophthalmic manifestations can involve both the anterior and posterior segment. Panophthalmitis is rare in dengue hemorrhagic fever, and there is no report of culture-positive panophthalmitis in this setting. Here, we report a case of a serology-positive 33-year-old male patient of dengue hemorrhagic fever who developed sudden onset pain, redness, and proptosis in the right eye. The patient subsequently developed panophthalmitis in his right eye, and Bacillus cereus was isolated from eviscerated sample. This case provides unique insights into pathogenesis of panophthalmitis in dengue and highlights the management options.

An imaging-based treatment algorithm for posterior focal retinitis

Background:

In this paper, our aim was to describe an imaging-based empirical approach for categorizing and initiating treatment of immunocompetent patients with posterior focal retinitis, prior to the availability of results of expensive laboratory investigations.

Materials and methods:

The hospital records of 13 patients with posterior focal retinitis were reviewed.

Results:

Of the 13 patients, 9 were women and 4 were men. The mean age was 24 ± 8 years. Based on similarities in clinical presentation and imaging, we categorized our cases into three groups with different first-line therapeutic strategies. In the first group, patients had presumed toxoplasmosis (treated with oral cotrimoxazole); in the second group, patients had presumed viral (herpetic) etiology (treated with oral valacyclovir); and in the third group, patients had presumed nonherpetic, nontoxoplasma retinitis (treated with oral doxycycline). Positive serology results included Rickettsia (two patients), Borrelia (one patient), Toxoplasma (two patients), and herpes simplex virus (one patient).

Conclusion:

An empirical approach for early initiation of therapy in retinitis cases based on imaging features is described.

Ocular manifestations of emerging arboviruses: Dengue fever, Chikungunya, Zika virus, West Nile virus, and yellow fever

Arboviruses are viral diseases transmitted by mosquitoes and tick bites. They are a major cause of morbidity and sometimes mortality. Their expansion is constant and due in part to climate change and globalization. Mostly found in tropical regions, arboviruses are sometimes the source of epidemics in Europe. Recently, the Chikungunya virus and the Zika virus were responsible for very large epidemics impacting populations that had never been in contact with those viruses. There are currently no effective antiviral treatments or vaccines. Ocular manifestations due to those infections are thus more frequent and increasingly better described. They are sometimes, as with Zika, complicated by a congenital ocular syndrome. The goal of this review is to describe the ophthalmological manifestations of Dengue fever, Chikungunya virus, Zika virus, West Nile virus, and yellow fever.

Isolated Horizontal Gaze Palsy: Observations and Explanations

We present three cases that we suggest require a novel diagnosis and a reconsideration of current understandings of pontine anatomy. In this case series, we highlight a series of patients with monophasic, fully recovering inflammatory lesions in the pontine tegmentum not due to any of the currently recognized causes of this syndrome. We highlight other similar cases in the literature and suggest there may be a particular epitope for an as-yet-undiscovered antibody underlying the tropism for this area. We highlight the potential harm of misdiagnosis with relapsing inflammatory or other serious diagnoses with significant adverse impact on the patient. In addition, we propose that this would support a reinterpretation of the currently accepted anatomy of the pontine gaze inputs to the median longitudinal fasciculus and paramedian pontine reticular formation.

Molecular Responses of Human Retinal Cells to Infection with Dengue Virus

Recent clinical reports indicate that infection with dengue virus (DENV) commonly has ocular manifestations. The most serious threat to vision is dengue retinopathy, including retinal vasculopathy and macular edema. Mechanisms of retinopathy are unstudied, but observations in patients implicate retinal pigment epithelial cells and retinal endothelial cells. Human retinal cells were inoculated with DENV-2 and monitored for up to 72 hours. Epithelial and endothelial cells supported DENV replication and release, but epithelial cells alone demonstrated clear cytopathic effect, and infection was more productive in those cells. Infection induced type I interferon responses from both cells, but this was stronger in epithelial cells. Endothelial cells increased expression of adhesion molecules, with sustained overexpression of vascular adhesion molecule-1. Transcellular impedance decreased for epithelial monolayers, but not endothelial monolayers, coinciding with cytopathic effect. This reduction was accompanied by disorganization of intracellular filamentous-actin and decreased expression of junctional molecules, zonula occludens 1, and catenin-β1. Changes in endothelial expression of adhesion molecules are consistent with the retinal vasculopathy seen in patients infected with DENV; decreases in epithelial junctional protein expression, paralleling loss of integrity of the epithelium, provide a molecular basis for DENV-associated macular edema. These molecular processes present potential therapeutic targets for vision-threatening dengue retinopathy.

Multimodal Imaging in Dengue-Fever-Associated Maculopathy

Dengue fever can cause ocular complications that may not be easily identified during a regular eye examination. A high degree of suspicion and multimodal imaging will help characterize the lesions during acute stages of the infection.

Ocular effects of Zika virus-a review

Zika virus was considered an innocent pathogen while restricted to the African and Asian population; however, after reaching the Americas in March 2015, it became a global threat. Despite usually causing mild or no symptoms in infected adults, Zika virus displays a different behavior toward fetuses. When infected during gestation, fetuses have their immature neural cells killed by the virus and consequently have devastating findings at birth. In the past year the drastic effects of Zika virus infection in newborns include neurological, ophthalmological, audiological, and skeletal abnormalities. These findings represent a new entity called congenital Zika syndrome. We summarize the ocular findings of congenital Zika Syndrome, as well as the current understanding of the illness, systemic manifestations, laboratory investigation, differential diagnosis, prophylaxis, and treatment for this disorder.

Dengue associated choroiditis: a rare entity

Background

We report a case of choroiditis during dengue fever.

Results

A 35-year-old female presented with blurring of vision during dengue fever. Her fundus examination revealed yellow deep choroidal lesions at right macula, multiple small, yellowish subretinal macular dots along papillomacular bundle, and hyperemic disc. There was a small retinal hemorrhage at temporal margin of disc. The left eye had similar small discrete lesion superonasal and inferotemporal to macula.

Conclusions

We report a hitherto undescribed case of choroiditis in a dengue patient.